1. Field of the Invention
The present invention relates to charge coupled devices and more particularly to charge coupled imagers having multispectral capability.
2. Description of the Prior Art
CCD imagers are well known in the prior art and have been used to replace vidicon tubes in black and white television cameras. For use in color TV applications, it has been necessary to use three CCD devices in conjunction with optical band-pass filters and appropriate image splitting optics to generate the conventional tri-color electrical signals.
The prior art requirement of multiple imager devices and their attendant multiple band-pass filters and sophisticated optics has precluded their widespread use in color TV applications. This is due to the fact that the separate CCD imagers and their band-pass filters must be matched as to their characteristics and the beam splitting optics must be carefully collimated in order to insure the proper operation of the resultant color TV camera. Furthermore, the optical band-pass filters and beam splitting optics add considerable weight and size to the camera. A color TV camera utilizing a CCD imager in accordance with the present invention eliminates the necessity for optical band-pass filters and beam splitting optics, thus allowing the fabrication of low-cost, lightweight color TV camera.
The CCD imager in accordance with the present invention is fabricated so as to have multiple collector structures utilizing multiple buried layers. The concept of using CCD devices having more than one buried layer is known in the art. For example, Krambeck, U.S. Pat. No. 3,739,240, is but one example of prior art which teaches a double buried channel CCD device. However, Krambeck does not teach or disclose a CCD device capable of collecting, detecting, storing, and transferring both holes and electrons as in the CCD imager in accordance with the present invention.